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      1 //===--- ParentMap.cpp - Mappings from Stmts to their Parents ---*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 //  This file defines the ParentMap class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #include "clang/AST/ParentMap.h"
     15 #include "clang/AST/Decl.h"
     16 #include "clang/AST/Expr.h"
     17 #include "llvm/ADT/DenseMap.h"
     18 
     19 using namespace clang;
     20 
     21 typedef llvm::DenseMap<Stmt*, Stmt*> MapTy;
     22 
     23 static void BuildParentMap(MapTy& M, Stmt* S) {
     24   for (Stmt::child_range I = S->children(); I; ++I)
     25     if (*I) {
     26       M[*I] = S;
     27       BuildParentMap(M, *I);
     28     }
     29 
     30   // Also include the source expr tree of an OpaqueValueExpr in the map.
     31   if (const OpaqueValueExpr *OVE = dyn_cast<OpaqueValueExpr>(S))
     32     BuildParentMap(M, OVE->getSourceExpr());
     33 }
     34 
     35 ParentMap::ParentMap(Stmt* S) : Impl(0) {
     36   if (S) {
     37     MapTy *M = new MapTy();
     38     BuildParentMap(*M, S);
     39     Impl = M;
     40   }
     41 }
     42 
     43 ParentMap::~ParentMap() {
     44   delete (MapTy*) Impl;
     45 }
     46 
     47 void ParentMap::addStmt(Stmt* S) {
     48   if (S) {
     49     BuildParentMap(*(MapTy*) Impl, S);
     50   }
     51 }
     52 
     53 Stmt* ParentMap::getParent(Stmt* S) const {
     54   MapTy* M = (MapTy*) Impl;
     55   MapTy::iterator I = M->find(S);
     56   return I == M->end() ? 0 : I->second;
     57 }
     58 
     59 Stmt *ParentMap::getParentIgnoreParens(Stmt *S) const {
     60   do { S = getParent(S); } while (S && isa<ParenExpr>(S));
     61   return S;
     62 }
     63 
     64 Stmt *ParentMap::getParentIgnoreParenCasts(Stmt *S) const {
     65   do {
     66     S = getParent(S);
     67   }
     68   while (S && (isa<ParenExpr>(S) || isa<CastExpr>(S)));
     69 
     70   return S;
     71 }
     72 
     73 Stmt *ParentMap::getParentIgnoreParenImpCasts(Stmt *S) const {
     74   do {
     75     S = getParent(S);
     76   } while (S && isa<Expr>(S) && cast<Expr>(S)->IgnoreParenImpCasts() != S);
     77 
     78   return S;
     79 }
     80 
     81 Stmt *ParentMap::getOuterParenParent(Stmt *S) const {
     82   Stmt *Paren = 0;
     83   while (isa<ParenExpr>(S)) {
     84     Paren = S;
     85     S = getParent(S);
     86   };
     87   return Paren;
     88 }
     89 
     90 bool ParentMap::isConsumedExpr(Expr* E) const {
     91   Stmt *P = getParent(E);
     92   Stmt *DirectChild = E;
     93 
     94   // Ignore parents that are parentheses or casts.
     95   while (P && (isa<ParenExpr>(P) || isa<CastExpr>(P))) {
     96     DirectChild = P;
     97     P = getParent(P);
     98   }
     99 
    100   if (!P)
    101     return false;
    102 
    103   switch (P->getStmtClass()) {
    104     default:
    105       return isa<Expr>(P);
    106     case Stmt::DeclStmtClass:
    107       return true;
    108     case Stmt::BinaryOperatorClass: {
    109       BinaryOperator *BE = cast<BinaryOperator>(P);
    110       // If it is a comma, only the right side is consumed.
    111       // If it isn't a comma, both sides are consumed.
    112       return BE->getOpcode()!=BO_Comma ||DirectChild==BE->getRHS();
    113     }
    114     case Stmt::ForStmtClass:
    115       return DirectChild == cast<ForStmt>(P)->getCond();
    116     case Stmt::WhileStmtClass:
    117       return DirectChild == cast<WhileStmt>(P)->getCond();
    118     case Stmt::DoStmtClass:
    119       return DirectChild == cast<DoStmt>(P)->getCond();
    120     case Stmt::IfStmtClass:
    121       return DirectChild == cast<IfStmt>(P)->getCond();
    122     case Stmt::IndirectGotoStmtClass:
    123       return DirectChild == cast<IndirectGotoStmt>(P)->getTarget();
    124     case Stmt::SwitchStmtClass:
    125       return DirectChild == cast<SwitchStmt>(P)->getCond();
    126     case Stmt::ReturnStmtClass:
    127       return true;
    128   }
    129 }
    130 
    131